In the case of “Deadpool 2,” keep on keeping on. Even more self-aware and self-referential than the original (and who knew that was even possible?), with a little extra heart (and a great new character) thrown in, it’s a lot of fun.

Julian Dennison plays Russell "Deadpool 2."(Photo: Joe Lederer)

This seems like the logical path for Reynolds, who shares writing credits with Phoenix natives Rhett Reese and Paul Wernick, who also wrote the original. (David Leitch takes over as director.) You could blow up the genre entirely, but come on, who are we kidding here? Genres are harder to kill than Wade Wilson himself.

For instance, however shocking the ending of “Avengers: Infinity War” might be to some, let’s remember that it’s the first half of a two-part story. “Deadpool 2” flirts with some serious issues of mortality, too, but that never gets in the way of the laughs.

Whether that’s a good thing or a bad one depends on what you want out of this kind of movie.

The film begins with a hilarious shot at another Marvel movie, setting the tone — once again, the fourth wall is more a custom than a rule for Wade. He seems to be getting comfortable as Deadpool in a superhero role, settling into a happy life with Vanessa (Morena Baccarin). Cynicism is still his greatest weapon (and without his mask, he still looks, as they said in the first movie, like a testicle with teeth), but overall life isn’t bad.

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Then tragedy strikes. If he veered toward pessimism before, now Wade is hurtling toward nihilism and the brakes have failed. He’s a sloppy drunk, hanging out at Weasel’s bar (T.J. Miller’s character will again live up to his name). Colossus (voice of Stefan Kapicic) plucks him out of his misery and tries to get him back on the right track. (The fact that it’s a Marvel movie and they only get B-grade X-Men characters is again a running joke, though with a blink-and-you’ll-miss-it twist.)

Deadpool begins training as a kind of X-Men intern. He tries to stop an angry mutant boy named Russell (Julian Dennison, so good in “Hunt for the Wilderpeople”), who’s gone ultra-violent at the home for mutant children where he lives. (Eddie Marsan plays the headmaster.) Deadpool smells a rat, things go sideways, and he and Russell wind up in a prison for mutants.

They don’t bond, exactly, despite Russell’s best efforts. Then a guy from the future named Cable shows up (Josh Brolin, fresh off of playing Thanos in “Avengers: Infinity War,” and if you think that goes unnoticed, you must not have seen the first “Deadpool”). He is after Russell, for reasons that will be explained over the course of time and many, many jokes and beheadings and disembowelments and call-backs and shots at other movies (including the D.C. universe).

Always on the hunt for another sequel, Deadpool forms X-Force (and indeed, a spin-off movie is in the works). The best of the new lot by far is Domino (Zazie Beetz), whose superpower is, simply, luck. If you’re dubious, so is Deadpool. But she’s not kidding. (She’s also badass.)

The way the filmmakers handle the new team is inspired; truly, it’s the most original thing in a movie like this in maybe ever. From here, however, the film turns into an origin story running alongside a redemption tale. The whole good guy-bad guy thing has always been flexible in Deadpool’s world, never more so than here. That’s part of the fun.

And “Deadpool 2” is, above all else, a lot of fun. (And yes, you must stay for the post-credit scenes.) Sometimes it maybe doesn’t take itself seriously enough (after about the 50th crack you do kind of want to tell Reynolds to hold off for a minute). But in a genre that takes itself so deadly seriously, this is like a breath of fresh air.